function sigma_F = maxMinGet(positions_F)
len_F = length(positions_F(:,1));
minDist = ones(len_F,1)*realmax();
for i=1:len_F
    nowP =positions_F(i,:);
    nowPB = positions_F;
    nowPB(i,:) = [];
    for j=1:len_F-1
        distV = nowP-nowPB(j,:);
        minDist(i) = min(minDist(i),norm(distV,2));
    end
end
sigma_F = max(minDist);
end